Change-speed gearing



Patented Jan. 2d, 19255 ADOLF LA'UB, OF BAS EL, SWITZERLAND ANO NYME, 0F EASEL, SWITZERLAND.

CHANGE-SFEED GEARING.

Application filed. June 26, 1924.

Y '0 all whom it may concern:

Be it known that I, ADOLF LAUB, a citizen of the Republic of Switzerland, and resident of Basel, Switzerland, have invented new and useful Improvements in Change- Speed Gearing, of which the following is a lull, clear, and exact specification.

This invention relates to change speed gearing of the type comprising a ring of pawls adapted to transmit: the motion of a driving rotary part to a driven rotary part, the pawls being adjustable in radial guide slots eccentrically to the axis of rotation of the driven part. In this type of gearing in which a ring of pawls arranged concentrically with a crown of teeth is provided, it has been proposed to utilize an annular shield which exposes the crown of teeth only at the point where the drive by the pawls is to be effected, and which acts as a device for controlling the action of the pawls, with a view to restricting this action of the pawls to one part only of the crown. It is also possible to arrange the device in such a manner that the ring of pawls can be dis placed in relation to the crown of teeth, the annular shield being maintained in a fixed position. This arrangement, however, possesses the disadvantage that the working position of the driving pawls is altered relative to the crown of teeth, when the ratio of transmission is altered, so that the driving action of the pawls becomes unreliable in certain circumstances, particularly when the pawls are constructed. in the form of long levers.

The subject matter of the present invention a gearing which, although bearing some resemblance to the above described well known form of construction, avoids the disadvantage above referred to. In accordance with the present invention the annular shield together with the crown of teeth and the driving pawls can be displaced relative to the axis of the gearing in such a manner as to maintain the driving pawls constantly in the same working position when the pawls are displaced.

The drawing shows a constructional example of the subject matter of the invention.

Figure l is a cross section, and

Figure 2 a longitudinal section thereof:

Figures 8 and ll are detail views.

A driving belt pulley a is fitted loosely upon and rotates about an annular body 5,

Serial l lo. 722,502.

which is mounted upon a movo'ble plate (7. The pulley a is provided internally with a crown of teeth (5. The driven rotary .pa-rt consists of a disc 0 rigidly secured to a shaft 7' which passes through a longitudinal slot in the annular body 7) and in the plate c. In radial lots c in the disc 6 are mounted. in the well known manner, pawls 7 controlled by springs and adapted to slide radially in the slots so as to work in con junction with the crown of teeth (Z. These pa-wls are pivoted at g to slicing blocks 71 guided in the said slots, and their springs tend to hold them in their engaging position. The annular body Z) is provided with a covering ring or shield i for the teeth (Z. At the point z" in this shield there is an opening extending over a certain distance. in the periphery of the said shield; and those pawls, the position of which does not coincide with this opening, are kept out of contact with the crown of teeth a? whilst the pawl or pawls which are situated within reach of the said opening are caused to mesh with the teeth of the crown of teeth (Z under the action of their springs.

The pivots g of the pawls g engage with a circular guiding slot 0 which is machined in the annular body 7) (Figure 4). and, when the said slot is displaced transversely relative to the shaft the 'pawls are displaced radially in the slots 6" of the disc 6.

The plate 0 together wi h the parts which it carries is secured to stud 7 which is guided in a slot m formed in the frame plate m. The stud can be displaced by means of a hand-lever a (Figure in such a manner that the body 7) can be adjusted to a coaxial or to a more or less eccentric position relative to the shaft 7 of the driven disc 6.

When the annular body 7) is placed coaxially relative to the shaft f of the disc c the ring of pawls is also coaxial with the disc 6 and the driving beltpulley (4 drives the disc 6 at the same speed. through the intermediary of the pawls which come one after the other within reach otthe opening 21 where the (ll'lVlllf action takes place. When the annular body 7) is displaced from its coaxial position and moved towards the left by means of the lover a. as shown in Fig ure 1, (there is no disadvantage in this displacement of the body provided that the belt runs on the pulley a perpendicularly to gear,

the direction of displacement) the ring of pawls is brought in a position which is eccentric to that of the shaft f, and any pawl g which comes within reach of the opening 2" in the covering shield 71 is brought into action on a larger radius, in such a manner that the rotary motion of the belt-pulley a is transmitted by the said pawl at a definite ratio of transmission, to the driven discc at the point where the drive is effected. The peripheral length of the opening 2" and the arrangement of the slots in the disc care for this purpose, so arranged that, prior to the pawl, which transmits the driving power, leaving the opening 2', the next successive pawl is already within the opening for the purpose of continuing the transmission of power. The greater the displacement towards the let't of the annular body I) as shown in Figure 1, the smaller the ratio of the transmission of power from the driving to the driven element. Arrangements are thus provided for obtain ing any desired ratio of transmission witl'iin definite limits by displacing the annular body 6 to a more or less considerable extent.

It willreadily be understood that the air nular body I) or the lever n employed for displacing the'said body can be arranged so as to be locked in any position required by any suitable mechanism such. as locking catches, or the like.

In order to enable the gearing to run idle when required a device is provided by which the pawls 9 can be prevented from engaging at the point where the driving actiontakes place. For this purpose two disengaging pins 1) are arranged in recesses in the annular body I). These pins are carried by a bridge 79 which is connected to a plunger 7 fitting within block 51 which is guided in a slot 071/ formed in the frame plate. An auxiliary lever s is provided pivoted at the point a on the lever a, the auxiliary lever 8 being in normal circumstances coupled with the lever a by means of a locking bolt t. The levers carries a bevelled lifting element a (Figure 2) by 111621118 of which, after releasing the lever n, the plunger '7 can be displaced axially (against the action of a spring), by turning the auxiliary lever s in such a manner that the pins p are brought within reach of the pawls during the rotation of the latter, and thus prevent the said pawls from assuming a position in which they can engage with the crown o1 teeth (Z when they enter the region in which the driving action takes place so that the pawls remain disconnected. p

The gearing described above is; particularly suitable as a substitute for cone pulearrics the ring of pawls could also Instead ofa belt-pulley a pinion could be employed which, when displaced, would re main continuously in rotary contact with the primary driving part. The disc which be the driving element and the disc fitted with the crown of teeth the driven element.

What Iclaim is:

1. A changeespeed gearing comprising a rotary driving element,za rotary driven element, a crown of teeth on one of these elements, a ring of eccentrically adjustable driving pawls on the other element for transmitting the motion, a covering ring or shield designed to control said pawls as regards their meshing and driving action and provided to this end with an opening at the place where the driving action shall take place, and means to 'displace'said covering ring together with the crown of teeth and the driving pawls relative to the axis of said other rotary element, in such a manner that the driving pawls, when displaced, are always kept in the same working position.

- 2. Achange speed gearing comprising a rotary driving element, a rotary driven element, a crown of teeth on one of these ele-. ments, a ring of eccentrically I adjustable driving pawls on the other element for transmitting the motion, a covering ring or shield designed to control said pawls as regards their meshing and driving action and provided'to this end with an opening at the place where the driving action shall take place, means to displace said covering ring together with the crown of teeth and the driving pawls relative to the axis of said other rotary element and a disengaging member at the opening in said covering ring normally kept out of engagement with the pawls and means to shiftsaididisengaging member within reach of the pawls in the course of rotation of the latter, so that the said pawls may be prevented from assuming the position in which they engage with the teeth. 7 7

"In witnesswhereot I have hereunto signed my name this l lth day of June, 1924, in the presence of two subscribingwitnesses.

g ADOLF LAUB.

Witnesses: V I

MADELEINE SrnNeLnR, v AMAND BRAUN. 

